Researchers have produced a photoswitch comprising just one photosensitive molecule whose electrical conductivity can be turned on and off by light. The device may, with further development, have potential in solar energy harvesting and light-sensing applications. It may also be useful in biomedical electronics and optical logic, in which light replaces electrical signals to transmit information.

ABSTRACT

Through molecular engineering, single diarylethenes were covalently sandwiched between graphene electrodes to form stable molecular conduction junctions. Our experimental and theoretical studies of these junctions consistently show and interpret reversible conductance photoswitching at room temperature and stochastic switching between different conductive states at low temperature at a single-molecule level. We demonstrate a fully reversible, two-mode, single-molecule electrical switch with unprecedented levels of accuracy (on/off ratio of ~100), stability (over a year), and reproducibility (46 devices with more than 100 cycles for photoswitching and ~105 to 106 cycles for stochastic switching).